As examples of a computer system or a communication system having a redundant configuration including a component of a waiting system in addition to a component of a main system, there are a duplex system, a dual system, and a multiprocessor system. Each of these systems has a feature of preventing a stop of the entire system by isolating a component in which a problem has arisen from the other components with a switch.
Patent Document 1 discloses a cell switch switching method in which a switching operation between an active cell switch and a standby cell switch is controlled by a system controller. Furthermore, Patent Document 2 discloses communication parts including electronic circuit packages used as an operating system or a waiting system, a switch which changes a system, and a switch control station which changes and controls the switch.